A simple server that saves key/value pairs

server.js

var http = require('http');

const storedValues = {};

http.createServer((request, response) => {

    // check path is supported
    const path = request.url.split('?');
    if (!path || path.length !== 2) {
        response.writeHead(404);
        response.end();
        return;
    }
    // check we have a valid key/value pair
    const keyValuePair = path[1].split('=');
    if (!keyValuePair || keyValuePair.length !== 2) {
        response.writeHead(400);
        response.end();
        return;
    }
    if (path[0] === '/set') {
        storedValues[keyValuePair[0]] = keyValuePair[1];
        response.writeHead(200);
        response.end(keyValuePair[1]);
        return;
    }
    else if (path[0] === '/get') {
        const returnValue = storedValues[keyValuePair[1]];
        if (returnValue === undefined) {
            response.writeHead(404);
            response.end('key not set');
        } else {
            response.writeHead(200);
            response.end(storedValues[keyValuePair[1]]);
        }
        return;
    } else { // unsupported path
        response.writeHead(404);
        response.end();
        return;
    }
}).listen(4000);